Hydraulic jack



April 1957 F. c. WILSON 2,789,788

HYDRAULIC JACK Filed Feb. 8, 1955 2 She'ets-Sheet 1 IN VEN TOR. F/M/vK6. WILSON April 23, 1957 F. c. WILSON I HYDRAULIC JACK Filed Feb. 8,1955 2 Sheets-Sheet'Z I INVENTOR. FRANK 6. WILSON BY ,W,M v

United States Patent Q HYDRAULIC JACK Frank C. Wilson, Arcade, N. Y.,assignor to K. R. Wilson, Inc., Arcade, N. Y.

' Application February s, 1955, Serial No. 486,756

' 4 Claims. 01. 254-2 My invention relates in general to hydraulic jacksand more particularly to the type used in the automobile industry.

It is desirable to quickly elevate the lifting arm of such a jack to thepoint of contact with the work before the load is raised. This issometimes accomplished by having two separate cylinders, the one oflarger area for quickly elevating the lifting arm, and the smaller oneof such size as to produce the necessary lifting power. Such aconstruction, however, requires intricate valve and actuatingmechanisms, and the employment of two separate cylinder systems.

The principal object of my invention is to provide mechanical means forquickly elevating the lifting arm to a point of contact with the load tobe lifted.

Another object is to provide such means which are independent of thehydraulic system, but which will when actuated place the hydraulicsystem in condition for immediate operation when it is desired to liftthe load.

A further object is to provide means connected with the usual pumpactuating handle for operating the quick lifting mechanism.

A further object is to provide ratchet means for actuating the liftingarm having an engaging pawl so designed that when the lifting armcontacts the load to be lifted, further actuation of the ratchet meanswill cause the pawl to become disengaged from the teeth of the ratchetwheel thus avoiding an attempt to raise the load by means of the ratchetdevice.

Moreover, my device is simple in design and of durable construction.

Furthermore, means are provided for locking the hy draulic pressurerelease means of the jack while operating the quick lifting means.

The above objects and advantages have been accomplished by the deviceshown in the accompanying drawings, of which:

Fig. 1 is a side elevation of a jack embodying my invention, portionsthereof being broken away;

Fig. 2 is a fragmentary plan view thereof;

Fig. 3 is an enlarged sectional fragmentary view showing the ratchetmeans;

Fig. 4 is an enlarged fragmentary side sectional view of my inventionshowing the pressure release locking means; and

Fig. 5 is a fragmentary plan view of the mechanism shown in Fig. 4.

The jack shown in the accompanying illustration comprises a jack framehaving spaced frame members 11 mounted on supporting wheels 12 andcaster wheels 13.

The jack is provided with a customary hydraulic cylinder 14 having theusual plunger 15. The lifting arm 16 of the jack is pivoted at 20 to theside members 11. The lower end 21 of the arm extends downwardly and ispivotally connected to the forward end of the hydraulic ram 15 by meansof the pivot pin 22. The usual swivel rest pad 23 is carried at theforward end of the lifting arm, and an auxiliary lifting arm 24 connectsthe pad with the lower part of the lifting arm 16in customary mannerwhereby a parallelogram is formed thus causing the pad to maintain itsvertical axis during movement.

The usual pump actuating handle 25 is provided for the jack and isconnected by the usual means (not shown) to the pump cylinder 14 andhydraulic reservoir (not shown) for raising the load in the usual andcustomary manner. This handle is mounted upon a pivot pin 26 carried bythe frame of the jack, and the handle carries the usual hydraulicrelease lever 30.

My invention comprises a segmentary ratchet wheel 31 mounted upon thehandle pivot 26. This ratchet wheel is formed with a downwardlyextending arm 32 which is pivotally connected to an actuating link 33.The actuating link extends forwardly and is connected to the pivot 22connecting the plunger with the lifting arm. The ratchet wheel islocated preferably on the inside of one of the side frame members 11 andbetween the side member and the lower end of the pump actuating handle.A pawl shaft 34 is pivotally carried by the lower end of the pumpactuating handle and a ratchet pawl 35 is attached to the outer end ofthis shaft in such position where it will register with the ratchetwheel. The pawl shaft 34 carries a ratchet lever 36 which is arrangedpreferably centrally of the actuating handle 25. The pawl lever extendsinwardly toward the central portion of the handle and a pawl actuatingrod 46 is attached thereto at its lower end. The upper end of this rodpasses through a bearing clip 41 carried at the upper end of the handleand is attached to an actuating button 42 secured to the upper end ofthe rod and extending through the handle. A helical spring 43 isdisposed between the bearing plate 41 and the lower end of the button42, whereby the ratchet pawl is normally disengaged from the ratchet.

The ratchet wheel is provided with a number of V-shaped ratchet teeth 44having outwardly flaring surfaces. The pawl engaging surfaces arearranged at such an angle that when engaged by the pawl the lifting armmay be elevated and the plunger withdrawn part-way from the cylinder.However, when the swivel rest pad reaches the load and further upwardmovement of the lift arm is attempted through the medium of the engagedratchet pawl, the angle of the engaging ratchet pawl surface is suchthat the ratchet pawl will be forced out of engagement with the teeth ofthe ratchet wheel, whereby it will be impossible to elevate the loadthrough the quick acting device. As a further precaution againsttransferring the load supported by the jack to the quick lifting device,I provide the usual pressure release arm 47 with a lock arm 45 extendingat substantially right angles to the release means 46 and which isnormally in the path of movement of the ratchet lever 36. The releasearm is actuated by the usual actuating rod 50 which is extended upwardlythrough the actuating handle and is connected for actuation to therelease lever 30.

It will be obvious that when the actuating rod 50 is pushed to cause therelease arm to actuate the hydraulic release lever, the lock arm 45 willbe moved toward the ratchet lever and cause the ratchet pawl to bedisengaged with the ratchet wheel before the jack is released to lowerthe load.

From the foregoing, it will be obvious that when the jack equipped withmy invention is placed under, for instance, an automobile, the swivelpad may be elevated with substantially one downward movement of theactuating handle after the ratchet pawl has become engaged with one ofthe adjacent teeth, thus enabling the operator with one single stroke toraise the pad up to and in contact with the surface of the load to belifted. During such elevating movement, the plunger will be drawnoutwardly within the cylinder, and hydraulic fluid will be drawn intothe cylinder which will thereby be filled when the jack is to beoperated to elevate the load. Since the swivel pad is elevated to theload by one stroke of the actuating handle, and since the cylinder isfilled Withoil, the load may be immediately lifted by actuating the pump(not shown) of the jack.

I vWhat is claimed is:

1. The combination with a hydraulic jack having a lifting arm and apivotally mounted actuating handle, of mechanical arm-lifting meanscomprising a ratchet wheel rotatably mounted upon the pivot of theactuating handle, a ratchet wheel arm carried by said ratchet wheel,said ratchet wheel having a series of teeth each having an inclinedworking surface, a manually actuated ratchet pawl pivotally carried bysaid actuating handle and having its forward end engageable with saidratchet teeth, the angular coacting surfaces of said pawl and engagedtooth being such as to become automatically disengaged when the liftingarm is subjected to pressure above a predetermined amount, and linkmeans connecting said ratchet wheel arm with said lifting arm, wherebydownward movement of said actuating handle may be used to cause saidlifting arm to be elevated only to the point of contact with the load tobe lifted.

2. The combination with a hydraulic jack having a lifting arm and apivotally mounted actuating handle, of mechanical arm-lifting meanscomprising a ratchet wheel rotatably mounted upon the pivot of theactuating handle, a ratchet wheel arm carried by said ratchet wheel,said ratchet wheel having V-shaped teeth, a manually actuated ratchetpawl pivotally carried by said actuating handle and having its forwardend engageable with said ratchet teeth, the angular coacting surfaces ofsaid pawl and engaged tooth being such as to become automaticallydisengaged when the lifting arm is subjected to pressure above apredetermined amount, and link means connecting said ratchet wheel armwith said lifting arm, whereby downward movement of said actuatinghandle will cause said lifting arm to be elevated to a point of contactwith the load to be lifted.

3. The combination with a hydraulic jack having a lifting arm, apivotally mounted actuating handle, and a hydraulic release mechanism,of mechanical arm-lifting means comprising a ratchet wheel rotatablymounted upon the pivot of the actuating handle, a ratchet wheel armcarried by said ratchet wheel, said ratchet wheel having a series ofteeth each having an inclined working surface, a manually actuatedratchet pawl pivotally carried by said actuating handle and having itsforward end engageable with said ratchet teeth, the angular coactingsurfaces of said pawl and engaged tooth being such as to'becomeautomatically disengaged when the lifting arm is subjected to pressureabove a predetermined amount, link means connecting said ratchet wheelarm with said lifting arm, and a lock arm carried by said hydraulicrelease means for engagement with said lifting means, whereby saidlifting means will be thrown out of engagement before said release meansis actuated.

4. The combination with a hydraulic jack having a lifting arm, apivotally mountedactuating handle, and a hydraulic release mechanism, ofmechanical arm-lifting means comprising a ratchet wheel rotatablymounted upon the pivot of the actuating handle, a ratchet wheel armcarried by said ratchet wheel, said ratchet wheel having a series ofteeth each having an inclined working surface, a manually actuatedratchet pawl pivotally carried by said actuating handle and having itsforward end engageable with said ratchet teeth, the angular coactingsurfaces of said pawl and engaged tooth being such as to becomeautomatically disengaged when the lifting arm is subjected to pressureabove a predetermined amount, link means connecting said ratchet wheelarm with said lifting arm, and a lock arm carried by said hydraulicalrelease means for engagement with said lifting means, whereby saidlifting means will be thrown out of engagement before said release meansis actuated.

References Cited in the file of this patent FOREIGN PATENTS 582,188Great Britain Nov. 7, 1946

